title: Photosystem II antenna phosphorylation-dependent protein diffusion determined by fluorescence correlation spectroscopy.
abstract: Flexibility of chloroplast thylakoid membrane proteins is essential for plant fitness and survival under fluctuating light environments. Phosphorylation of light-harvesting antenna complex II (LHCII) is known to induce dynamic protein reorganization that fine-tunes the rate of energy conversion in each photosystem. However, molecular details of how LHCII phosphorylation causes light energy redistribution throughout thylakoid membranes still remain unclear. By using fluorescence correlation spectroscopy, we here determined the LHCII phosphorylation-dependent protein diffusion in thylakoid membranes isolated from the green alga Chlamydomonas reinhardtii. As compared to the LHCII dephosphorylation-induced condition, the diffusion coefficient of LHCII increased nearly twofold under the LHCII phosphorylation-induced condition. We also verified the results by using the LHCII phosphorylation-deficient mutant. Our observation suggests that LHCII phosphorylation-dependent protein reorganization occurs along with the changes in the rate of protein diffusion, which would have an important role in mediating light energy redistribution throughout thylakoid membranes.
authors.affiliation: 1] Live Cell Molecular Imaging Research Team, Extreme Photonics Research Group, RIKEN Center for Advanced Photonics, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan [2] PRESTO, Japan Science and Technology Agency, 4-1-8 Honcho, Kawaguchi, Saitama 332-0012, Japan.
authors.forename: Masakazu
authors.initials: M
authors.lastname: Iwai
authors.forename: Chan-Gi
authors.initials: CG
authors.lastname: Pack
authors.forename: Yoshiko
authors.initials: Y
authors.lastname: Takenaka
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Sako
authors.forename: Akihiko
authors.initials: A
authors.lastname: Nakano
mesh_terms: D020418:Algal Proteins / Q000378:metabolism*; D016825:Chlamydomonas reinhardtii / Q000378:metabolism*; D004058:Diffusion; D005453:Fluorescence; D008027:Light; D045342:Light-Harvesting Protein Complexes / Q000378:metabolism*; D010766:Phosphorylation; D010788:Photosynthesis; D045332:Photosystem II Protein Complex / Q000378:metabolism*; D013050:Spectrometry, Fluorescence / Q000379:methods*; D020524:Thylakoids / Q000378:metabolism*
chemical_list: D020418:Algal Proteins; D045342:Light-Harvesting Protein Complexes; D045332:Photosystem II Protein Complex